London has been battered by 50mph winds that have felled trees and caused travel chaos. Powerful gusts swept across the capital as the Met Office issued a yellow "be aware" weather alert for most of the country.

Scotland Yard detectives are preparing to fly to Libya again in the pursuit of the killers of London policewoman Yvonne Fletcher.

Investigators are said to be receiving a degree of co-operation from the new authorities in Tripoli following the death of former dictator Muammar Gaddafi. David Cameron revealed during a visit to the North African state yesterday that Scottish police investigating the Lockerbie bombing are to fly out to the country for the first time.

WPc Fletcher, 25, was murdered in 1984 while policing an anti-Gaddafi protest outside the Libyan embassy in London. No one was ever charged with her killing and suspects from inside the embassy were allowed to leave under diplomatic immunity. A former junior diplomat has been identified as prime suspect.

Mr Cameron’s tour of North Africa was finishing today in Liberia where he co-chaired a UN poverty conference.